Cyclobenzaprine, or 3-(5H-dibenzo[a,d]cyclohepten-5-ylidene)-N,N-dimethyl-1-propanamine, was first approved by the U.S. Food and Drug Administration in 1977 for the treatment of acute muscle spasms of local origin. (Katz, W., et al., Cyclobenzaprine in the Treatment of Acute Muscle Spasm: Review of a Decade of Clinical Experience, Clinical Therapeutics 10:216-228 (1988)). Cyclobenzaprine has also been studied in the treatment of fibromyalgia. In a study of 120 fibromyalgia patients, those receiving cyclobenzaprine (10 to 40 mg) over a 12-week period had significantly improved quality of sleep and pain score. There was also a reduction in the total number of tender points and muscle tightness (Bennett R M. et al. A Comparison of Cyclobenzaprine and Placebo in the Management of Fibrositis: A Double-Blind Controlled Study, Arthritis Rheum. 1988; 31(12):1535-42).
Furthermore, the utility of a very low dose cyclobenzaprine as an agent for improving the quality of sleep, as a sleep deepener, or for treating sleep disturbances has been investigated. The very low dosage regimen was viewed as particularly useful in treating sleep disturbances caused by, exacerbated by or associated with fibromyalgia syndrome, prolonged fatigue, chronic fatigue, chronic fatigue syndrome, a sleep disorder, a psychogenic pain disorder, chronic pain syndrome (type II), the administration of a drug, autoimmune disease, stress or anxiety or for treating an illness caused by or exacerbated by sleep disturbances, and symptoms of such illness and generalized anxiety disorder. See U.S. Pat. Nos. 6,395,788 and 6,358,944, herein incorporated by reference.
It is important to develop new methods and pharmaceutical compositions that ameliorate fatigue associated with disordered sleep to improve symptoms found in fibromyalgia, multiple sclerosis, Fabry's disease, traumatic brain injury or Parkinson's disease.